Electronics

Beyond the expense of the devices themselves, gadgets like laptops, cell phones, and thumb drives contain information that could be easy to steal. If you’re in a position where you have to store your laptop or phone unattended, make sure the information is encrypted, says Eva Velasquez, CEO and president of Identity Theft Resource Center. This makes thieves unable to view information without a code, separate from the password used to log in to the device. “It’s a strong layer of protection and would need someone putting a fair amount of effort into it to view,” Velasquez says. “It’s much stronger than password protection.”

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Sunscreen

Ironically, the active ingredients in sunscreen break down in high heat. Leaving it in the car on a hot day could reduce its effectiveness. Plus, the heat could cause it to explode, leaving you with a hot mess.

Water bottles

Although the research is a bit unclear, studies have linked BPA and phthalates, chemicals found in plastic water bottles, with health conditions like cancer and heart disease. Letting a bottle sit in the sun and heat up could cause these chemicals to leach into the water. Plus, if the bottle has been lying around for a while, it could start harbouring microorganisms.

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Handbag

Leaving a purse or wallet in plain sight makes your car a target for thieves, even if you’ve locked your doors or taken the valuables out of your bag. “It doesn’t matter if the alarm goes off,” Velasquez says. “It’s attractive, and they’re going to grab it.”

Glasses

Take advantage of your car’s sunglasses compartment while driving, but don’t leave your shades in it after you reach your destination. Heat can warp plastic frames and make metal ones too hot to wear. Leaving your glasses or sunglasses on the dashboard is even worse because the windshield could attract sunlight like a magnifying glass, American Optometric Association spokeswoman Susan Thomas has said.

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Important documents

If you have personal documents that you plan to mail or shred, make that task a priority on your to-do list. Letting files like school transcripts or tax forms sit in your car while you run other errands or until you have time to take care of them leaves information vulnerable if anyone breaks into your vehicle, Velasquez says. “Put it in the car, take care of it, and then you’re done,” she says. “You have to follow through.”

Passport

Never leave a passport in the car while travelling, even if it seems like it’s too bulky to carry around. Identity theft is even easier with a passport than with a driver’s license, Velasquez says. “We have to think of data and pieces of our identity as valuables,” she says. “You’re not going to leave jewelry in the car, but we don’t have that same level of concern with things that make up our identity, and we need to.”

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Wine

Wait until after work or errands to pick up a bottle of wine. If the bottle gets too hot, the flavour could be affected, and the liquid could expand enough to seep around the cork or push the cork out a bit, contaminating the wine inside.

Young children

Even if you don’t expect an errand to take more than a few minutes, leaving children alone in the car on a hot day puts their safety at risk. On average, 38 children die every year from heatstroke in hot cars (no Canadian statistics are available). The air temperature in a previously air-conditioned small car exposed to the sun on a 35ºC day can exceed 50ºC within 20 minutes, according to a study conducted by General Motors.

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Pets

Dogs and cats are also at risk in hot summertime temps. Hundreds of pets die every year in the United States from overheating in vehicles, according to the American Veterinary Medical Association.

Groceries

Save your grocery run for the end of your errands list. Perishable food should be put in the fridge within two hours in most cases. In the summer, you have an even shorter window.

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Indoor plants

Consider the weather before heading to a gardening centre, especially if you won’t be heading home straight after. Even relatively mild temperatures of 7°C to 10°C can kill some plants within an hour, according to Lowe’s. If the leaves are touching the windows, the chilly glass could ruin the foliage. Hot temperatures can also be deadly to plants, so keep them shaded and cool on your drive home, and bring them indoors as soon as possible.

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Aerosol cans

There’s a reason for the fine print on aerosol cans’ warning labels: as the product’s temperature climbs, so does the pressure inside that lets it spray continuously. In rare cases—like a woman in Arizona and a man in England experienced last summer—the heat in a car can get so intense that the aerosol explodes, especially if you leave it in direct sunlight. The projectile can damage the car, or worse, hit somebody with a force strong enough to send them to the hospital.

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Lipstick

Your favorite tube won’t stand a chance in the sky-high summer temperatures. Keep lipstick from turning into an unusable, melted mess by toting it in and out, rather than leaving it in the car for touch ups in front of the sun visor mirror.